package com.elock.util;

/**
 * 点工具类
 * @author 仁德
 */
public class PointUtil {

	public static double pi = 3.1415926535897932384626;
	public static double a = 6378245.0;
	public static double ee = 0.00669342162296594323;

	private static double EARTH_RADIUS = 6371;

	/** 
	 * 通过经纬度获取距离(单位：米) 
	 * @param lat1 
	 * @param lng1 
	 * @param lat2 
	 * @param lng2 
	 * @return 
	 */
	public static double getDistance(double lat1, double lng1, double lat2, double lng2) {
		double radLat1 = rad(lat1);
		double radLat2 = rad(lat2);
		double a = radLat1 - radLat2;
		double b = rad(lng1) - rad(lng2);
		double s = 2
				* Math.asin(Math.sqrt(Math.pow(Math.sin(a / 2), 2)
						+ Math.cos(radLat1)
								* Math.cos(radLat2)
								* Math.pow(Math.sin(b / 2), 2)));
		s = s * EARTH_RADIUS;
		s = Math.round(s * 10000d) / 10000d;
		s = s * 1000;
		return s;
	}

	private static double rad(double d) {
		return d * Math.PI / 180.0;
	}

	/**
	 * 84 to 火星坐标系 (GCJ-02) World Geodetic System ==> Mars Geodetic System
	 * 
	 * @param lat
	 * @param lon
	 * @return
	 */
	public static double[] gps84_To_Gcj02(double lat, double lon) {
		if (outOfChina(lat, lon)) {
			return null;
		}
		double dLat = transformLat(lon - 105.0, lat - 35.0);
		double dLon = transformLon(lon - 105.0, lat - 35.0);
		double radLat = lat / 180.0 * pi;
		double magic = Math.sin(radLat);
		magic = 1 - ee * magic * magic;
		double sqrtMagic = Math.sqrt(magic);
		dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
		dLon = (dLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * pi);
		double mgLat = lat + dLat;
		double mgLon = lon + dLon;
		return new double[] { mgLat, mgLon };
	}

	/**
	 * * 火星坐标系 (GCJ-02) to 84 * * @param lon * @param lat * @return
	 * */
	public static double[] gcj_To_Gps84(double lat, double lon) {
		double[] GpsPoint = transform(lat, lon);
		double lontitude = lon * 2 - GpsPoint[1];
		double latitude = lat * 2 - GpsPoint[0];
		return new double[] { latitude, lontitude };
	}

	/**
	 * 火星坐标系 (GCJ-02) 与百度坐标系 (BD-09) 的转换算法 将 GCJ-02 坐标转换成 BD-09 坐标
	 * 
	 * @param gg_lat
	 * @param gg_lon
	 */
	public static double[] gcj02_To_Bd09(double gg_lat, double gg_lon) {
		double x = gg_lon, y = gg_lat;
		double z = Math.sqrt(x * x + y * y) + 0.00002 * Math.sin(y * pi);
		double theta = Math.atan2(y, x) + 0.000003 * Math.cos(x * pi);
		double bd_lon = z * Math.cos(theta) + 0.0065;
		double bd_lat = z * Math.sin(theta) + 0.006;
		return new double[] { bd_lat, bd_lon };
	}

	/**
	 * * 火星坐标系 (GCJ-02) 与百度坐标系 (BD-09) 的转换算法 * * 将 BD-09 坐标转换成GCJ-02 坐标 * * @param
	 * bd_lat * @param bd_lon * @return
	 */
	public static double[] bd09_To_Gcj02(double bd_lat, double bd_lon) {
		double x = bd_lon - 0.0065, y = bd_lat - 0.006;
		double z = Math.sqrt(x * x + y * y) - 0.00002 * Math.sin(y * pi);
		double theta = Math.atan2(y, x) - 0.000003 * Math.cos(x * pi);
		double gg_lon = z * Math.cos(theta);
		double gg_lat = z * Math.sin(theta);
		return new double[] { gg_lat, gg_lon };
	}

	/**
	 * (BD-09)-->84
	 * @param bd_lat
	 * @param bd_lon
	 * @return
	 */
	public static double[] bd09_To_Gps84(double bd_lat, double bd_lon) {

		double[] gcj02 = bd09_To_Gcj02(bd_lat, bd_lon);
		double[] map84 = gcj_To_Gps84(gcj02[0], gcj02[1]);
		return map84;

	}

	public static boolean outOfChina(double lat, double lon) {
		if (lon < 72.004 || lon > 137.8347) return true;
		if (lat < 0.8293 || lat > 55.8271) return true;
		return false;
	}

	public static double[] transform(double lat, double lon) {
		if (outOfChina(lat, lon)) {
			return new double[] { lat, lon };
		}
		double dLat = transformLat(lon - 105.0, lat - 35.0);
		double dLon = transformLon(lon - 105.0, lat - 35.0);
		double radLat = lat / 180.0 * pi;
		double magic = Math.sin(radLat);
		magic = 1 - ee * magic * magic;
		double sqrtMagic = Math.sqrt(magic);
		dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
		dLon = (dLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * pi);
		double mgLat = lat + dLat;
		double mgLon = lon + dLon;
		return new double[] { mgLat, mgLon };
	}

	public static double transformLat(double x, double y) {
		double ret = -100.0
				+ 2.0 * x
				+ 3.0 * y
				+ 0.2 * y * y
				+ 0.1 * x * y
				+ 0.2 * Math.sqrt(Math.abs(x));
		ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi))
				* 2.0
				/ 3.0;
		ret += (20.0 * Math.sin(y * pi) + 40.0 * Math.sin(y / 3.0 * pi)) * 2.0 / 3.0;
		ret += (160.0 * Math.sin(y / 12.0 * pi) + 320 * Math.sin(y * pi / 30.0))
				* 2.0
				/ 3.0;
		return ret;
	}

	public static double transformLon(double x, double y) {
		double ret = 300.0
				+ x
				+ 2.0 * y
				+ 0.1 * x * x
				+ 0.1 * x * y
				+ 0.1 * Math.sqrt(Math.abs(x));
		ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi))
				* 2.0
				/ 3.0;
		ret += (20.0 * Math.sin(x * pi) + 40.0 * Math.sin(x / 3.0 * pi)) * 2.0 / 3.0;
		ret += (150.0 * Math.sin(x / 12.0 * pi) + 300.0 * Math.sin(x / 30.0 * pi))
				* 2.0
				/ 3.0;
		return ret;
	}

	//GPS84坐标转换成百度坐标
	public static double[] gps84_to_bd(double lat, double lon) {

		double[] gcj = gps84_To_Gcj02(lat, lon);
		if (gcj == null) {
			return new double[] { 0, 0 };
		}
		double[] bd = gcj02_To_Bd09(gcj[0], gcj[1]);
		return bd;
	}

	public static void main(String[] args) {

		System.out.println(getDistance(22.925897, 113.221328, 22.925851, 113.22091));
	}
}
